Name:
Vaccinium uliginosum - Rhododendron lapponicum / Juncus trifidus Dwarf-shrubland
Reference:
Eastern Ecology Working Group of...
Description:
Alpine meadows of matted shrubs, sedges, and rushes are the dominant vegetation above treeline on the highest peaks of the northern Appalachian Mountains. Typically they occur above 4500 feet (occasionally lower) on exposed mountain summits, ridges, and bedrock-dominated tablelands. The substrate ranges from gravelly flats to jumbled rocks to stone pavements, with limited soils: basically well-drained gravels and stones with shallow organic accumulation. Protected spots may have continuous atmospheric moisture. The short snow-free season, frequent fog, cutting winds, and intense solar radiation are hallmarks of this environment. The vegetation is often patchy, with some areas shrub-dominated and other patches graminoid-dominated, but overall, dwarf-shrubs predominate. Shrub cover is usually 40-60%; herb cover is typically less, but may be up to 50% in some spots. Tree species may be present in shrub form in scattered, somewhat sheltered pockets. Bryophytes are very limited, but lichens may be abundant. Characteristic dwarf-shrubs are Vaccinium uliginosum, ubiquitous in this association, with Vaccinium vitis-idaea, Vaccinium boreale, Betula nana (= Betula glandulosa), Empetrum nigrum, Empetrum eamesii ssp. atropurpureum, Rhododendron lapponicum, Diapensia lapponica, Salix uva-ursi, and Arctostaphylos uva-ursi. Graminoids scattered among the shrubs, and in places codominant, are primarily Juncus trifidus and Carex bigelowii. Sibbaldiopsis tridentata (= Potentilla tridentata) is a common forb, as is Minuartia groenlandica, which typically grows in the more gravelly substrates, often along trails. Herbs that are not abundant, but characteristic, include Solidago multiradiata, Hierochloe alpina, Agrostis mertensii, Prenanthes boottii, and Huperzia appalachiana. The combination of alpine heath shrubs in a mosaic with alpine graminoids is diagnostic. This is the above tree-line "matrix" type in which other, more limited and specialized alpine associations found on the more extensive summits are embedded. These include Diapensia lapponica Dwarf-shrubland (CEGL006322), Vaccinium uliginosum - Harrimanella hypnoides - Loiseleuria procumbens Dwarf-shrubland (CEGL006155), Carex bigelowii Herbaceous Vegetation (CEGL006081) and Empetrum nigrum - Vaccinium uliginosum - Vaccinium oxycoccos / Rubus chamaemorus Dwarf-shrubland (CEGL006140).
Accession Code:
VB.CC.24564.VACCINIUMULIGIN
Plot-observations of this Community Concept:
0
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